The present disclosure relates to respiratory therapy systems and devices. More particularly, it relates to respiratory therapy systems, and pressure pulse generators or driver units useful as part of the system, capable of providing multiple modes of operation including delivery of respiratory pressure pulses to a patient (e.g., high frequency intrapulmonary percussive ventilation).
A wide variety of respiratory therapy devices are currently available for assisting, treating, or improving a patient's respiratory health. For example, positive airway pressure (PAP) has long been recognized to be an effective tool in promoting bronchial hygiene by facilitating improved oxygenation and increased lung volumes. More recently, PAP has been recognized as useful in promoting mobilization and clearance of secretions (e.g., mucous) from a patient's lungs. In this regard, positive airway pressure in the form of high-frequency assisted airway clearance (HFAAC) of the patient's air column is a recognized technique that facilitates secretion removal. In general terms, HFAAC devices reduce the viscosity of sputum in vitro, which in turn has a positive effect on clearance induced by a simulated cough. HFAAC can be delivered or created via a force applied to the patient's chest wall (i.e., chest physical therapy (CPT)), or by applying forces directly to the patient's airway (i.e., breathing treatment, such as high frequency intrapulmonary percussive ventilation (IPV)). Many patients and caregivers prefer the breathing treatment approach as it is less obtrusive and more easily administered. To this end, IPV techniques have emerged as an effective alternative to CPT for expanding the lungs and mobilizing secretions.
Various IPV treatment systems are available for providing the respiratory therapy (high frequency intrapulmonary percussive ventilation) described above (as well as other therapies and/or ventilation). In general terms, the high frequency IPV system includes a hand-held device establishing a patient breathing circuit to which a source of positive pressure gas (e.g., air, oxygen, etc.) is fluidly connected. In this regard, the system further includes a driver unit that acts upon the supplied positive pressure gas, creating a pressure profile or otherwise effectuate intermittent flow of gas into the patient breathing circuit, and thus percussive ventilation of the patient's lungs. With this approach, the patient breaths through the breathing circuit's mouthpiece (or mask), that in turn delivers the generated high-flow, “mini-bursts” of gas to the patient's airways. The pulsatile percussive airflow periodically increases the patient's airway pressure.
Current driver units rely upon pneumatic valves to generate/control the pressure profile delivered to the patient breathing circuit and thus the patient. Examples of IPV devices incorporating this “active” driver approach include IPV® Ventilator Devices (from PercussionAire Corp., of Sandpoint, Id.) and PercussiveNeb™ system (from Vortran Medical Technology, Inc., of Sacramento, Calif.). While these and other available IPV systems may provide other modes of operation in addition to IPV therapy (e.g., delivering positive airway pressure and/or aerosol delivery), the pneumatic valving approach overtly limits available frequency and/or pressure ranges deliverable to a patient. Other system drawbacks, such as limited or no feedback-based valve control, difficulties in establishing and maintaining desired control settings, etc., also exist.
In light of the above, a need exists for improved respiratory therapy systems, and driver units useful with such systems, that more consistently deliver a desired IPV therapy (as well as other therapies) to a patient.